Method of reducing ores.



. R.' S: WILE. METHOD 01?4 REDUGING GRES. APPLICATION FILED DBO. 2A, 191.3.

. u'lrruzsysss mvENT'on Limo-.n

` -I'UNrTED sTArnsprarENT OFFICE.

RAYMOND S. WILE, PITTSBURGH, PENNSYLVANIA.

METHOD or REDUCING ones.

T o all whom it' may concern.: l

Bc'it known that I, RM'Moxn S. lViLn, a 'citizen of the United States, residing at Iittsburgh, in the county of Allegheny and State of Pennsylvania@ave invented a new and useful Improvemei'it in Methods of -l-{educing Orcs, of which the follow-'ing is a full, clear, and exact description, reference being had to the accompanying drawing forming part of this specification, in \vhich`.

Figure l is a-vertical central section of au lectricfurnace designed for carrying out my invention; Fig. il is afront elevation of the same; and Fig. Sis a bottom-plan view.

My invention relates to the reducing of ores and is designed to proiide a cheap and efficient electric method by which ores may be. reduced to 1nattes, metals or other elements or compounds carried thereby.

-To -that end, the invention consists in maintaining a bath of slag by means of an electric current which passes through the same in a vertical direction, thereby keeping it under control as to temperature and feed- -ing intO the upper part of said hath the ore to be reduced, thereby partially or wholly reducing theore andtapping it out at the bo'ttom from time to time, as desired. In this connection, I also preferably maintain the slag bath at such a density that the ore' is held' above the bath for a suliicient period to volatilize at least a part of its volatilizable deleterious compounds, such, for ex- A j.' `taI'Jere ample, as arsenic or sulfuror their compounds, prior to the ore entering the bath and becoming melted. I alsopreferably employ a relatively deep bath of slag and. a relatively high voltage of current, preferably over two hundred volts, in order to .properly carry out my process in a continuous manner, since thereby a variation of ten `to-twenty-five volts in the current docs not `materially interfere with or prevent the proper carrying out of the process.

I will now describe my process as applied .to copper-bearing ores which may also contain precious metals and usually-sulfur or its compounds. In such case, I have used a relatively small ,furnace of fifteen to fifty tons capacity, such, for example, as shown in .the drawings. In this case, the electric. 4fur.- nace is a vessel 2 of generally cylindrical form, referably'having its lower portion '3 downwardly and inwardly slightly and out inwardly on one side at 4 to reduce the length of the tap holes, rIbis vessel may Specification of Letters Patent.

'Application alec December 2, 1913. Serial No. 804,202.

may be similar to the ore charge, preferably Patented Sept. 22, 1914i'.

be formed of sheet steel and is lined with refractory material 5, 'preferably bricks of high refractory natrue, 'such as chrome or magnesite. 'lhe vessel is formed,.\\'ith a lower metal tap hole (3 and a slag tap hole (5 at a higher level, the bottom of the vessel having a hole or holes T to receive the lower electrode or electrodes S. depends into the open top of the furnace.

, In starting the operatic-n, I drop into the An electrode -9 furnace cold slag-forming materials which.

containing suliieient slag-forming material to malte a slag having about fifty per cen silica. The upper electrode lia-ving been lowered into contact with the lower electrode, ythe cold charge-is put in, the current is turned on and the electrodes -ai'e gradually separat-ed, thus melting the slag-forming material until a slag bath is formed. '.lhis slag bath is preferablyof a depth of three feet or more, the upper electrode 'at this time dipping into theJ upper part of the bath while the lower part of the bath-contacts with the lower electrode, the current V passing vertically through the bath. In the l majority of cases, I prefer to use an alter nating current, and as above stated; a. ourrent of high voltage-'over two hundred volts. gradually into the top of the furnace around the upper electrode, and this ore rest-s on the top of the `molt-en slag bath, because the ore is of less specific gravity than that of the bath. As the ore thus lies on the top of the bath, it becomes heated to a temperature where its volatilizable compounds pass off as fumes. Thus, deleterious elements and con'ipounds, such Aas arsenic and possibly zinc, are driven oil by volatilization before the ore enters the slag bath. As more ore is supplied, the ore column gradually sinks intol the slag bath and its lower portion becomes melted lin the bath and descends through it, .forming a pool of reduced or partially reduced material lying in the bottom of the furnace. This lower molten bath may be either a matte, a metal or .otherelement or compounil-reduced froml the ore. 'l he operation. then goes on continuously, the metal being tapped oil from time totime, as desired, preferably every few hours thrl ugh the metal tap hole, and the slag being tapped oi'at the upper tap` hole to' maintain the slag bath at about the desired depth. Thisl The ore to be reduced is then fed 'matter of feet rather than inches.

proximately consta-nt throughout the entiic smelting operation, since thereby I am enabled to keep the temperature of the .bath as well as its density approximatel at the desired point. This point will, o course, vary somewhat with tie special kind of ore being treated, but when once ascertained and fixed for such .special ore, is maintained at the desired point. The tap holes are, of course, opened and'c'losed by the usual plugs which are inserted and removed by hand.

By using a relatively deep slag bath and a higher voltage of electric current, I am enabled to keep the slag bath of substantially the sa-me temperature through-out its different parts. thus l'naking the pi'oeess-\inifor1 n in the diffe-rent parts of the bath.

By the term "'rleep, as used herein andl in the claims vwith reference taai-32e slag` bath, 'I refer to a bath whose depth is a While the exact depth will, of course, depend u on the size and particular character of the urnare this depth lshould'in all cases. be in excess of the diameter of the in-feeding ore charge and preferably in no-e'ase less than one=and one-half feet. This not only enables the use of'muc-h higher voltages and I y these compounds,`as is generally the case, I

add tliese slagforming compounds or elements to .the ore, the mixture beingfed in as" above stated. r

The advantages of my-invention will be obvious to those skilled the art, since a` rapid and effective reduction of'ores is ob'- tained by electric heat. -The process is especially advantageous in districts where proper fuels are difficult to get, and furtherused for both upper and lower electrodev systems, as shown in my Patent, No. 1,070,568, dated Au ust 19, 1913,1particula-rly for larger size furnaces. The shape and' character of thefurnac'e may -be'varied,

different kinds of ores may be treated, and other variations may be made' without departing from myinvention.

1. The. method of reducing ores, which consists in continuouslyr maintaining a deep slag bath by passing an electric current vertically/through the central portion ofthe bath, feeding ore into the upperportion of the bath, and maintaining said bath'atan approximately constant-depth and of a relatively high density whereby the ore is held above the bath for a sufficient period to volatilize4 toa maximum extent the volatilizable materials, if any, in the ore; substantially as described.

2. The method' o1' :reducing ores, which consists in forming a deep sla bath, feeding ore into the upper portion .o the bath, and

' passing an electric current through the centrai portion ofthe Abath,l maintaining the bath at a substantially constant depth and of a relatively high density whereby the ore is held above the'bath fora suicie'nt period .to volatilize to'a maximum extent the volatilizable materials, if any, inthe ore, and affording a free escape .for thel volatilized materialsthrouo'h the in-feeding ore and at the top of the furnace; substantially as de- I scribed. y

In testimony whereof, -I have hereunto set my hand.

' RAYMOND S. VILE. l Witnesses:

HARRY A. Nima, Jr. J Amis B. DouNELLY. 

